hello - have a freshly rebuilt 350 - idles good and runs good on top end but if you really snap the throttle quick she cuts out - noticed when tuning carb the vaccum was fine (18 - 20) at idle - and higher when revved up but when you'd hit the throttle real quick the vaccum guage would drop way down - do i need a vaccum canister or does this mean i have a leak?
350 chevy hesitation question
- Thread starter rdub420
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Check your float level..it cuts out? i think its running a bit lean.... unless it belches out smoke when you stab the throttle.
350 engine
it helps to know what carb your dealing with? first thing i would check your accelerator pump!!!! you can do this with out running your engine by looking down the throat of your carb and opening your throttle to see if fuel squirts into the throttle if so check the timing if you have a vaccum advance on your dist you needtosee if it's idle vaccum or throttle vaccum there are different ports on your carb some are idle vaccum some are ported vaccum that means it has vaccum at part throttle opening you also need to check your mechanical advance for proper operation just so you'll know all vaccum falls off temporarily with wide open throttle 😀 i hope this helps you good luck ps remember to shut your engine off to check accelerator pump!!!!!!
it helps to know what carb your dealing with? first thing i would check your accelerator pump!!!! you can do this with out running your engine by looking down the throat of your carb and opening your throttle to see if fuel squirts into the throttle if so check the timing if you have a vaccum advance on your dist you needtosee if it's idle vaccum or throttle vaccum there are different ports on your carb some are idle vaccum some are ported vaccum that means it has vaccum at part throttle opening you also need to check your mechanical advance for proper operation just so you'll know all vaccum falls off temporarily with wide open throttle 😀 i hope this helps you good luck ps remember to shut your engine off to check accelerator pump!!!!!!
when you snap the throttle open then closed the vac should drop and then spike before returning to normal.
your vac is great at 18-20, there is no need for a canister. you need them when idle vac goes under about 10 ay idle.
your vac is great at 18-20, there is no need for a canister. you need them when idle vac goes under about 10 ay idle.
When you open the throttle, more air passes through the carburetor so the vacuum will drop. That's why the power circuit exists, to make up for that lack of vacuum. This doesn't respond immediately to enrich the mixture, so the accelerator pump is on place to squirt extra fuel when you step on the accelerator.
As JESSE said, check the accelerator pump (it's really easy). If this is working, check your float and your power circuit. I'm assuming it's a Quadrajet, so IIRC, there's a cam on the secondary side that activates the secondary metering system.
As JESSE said, check the accelerator pump (it's really easy). If this is working, check your float and your power circuit. I'm assuming it's a Quadrajet, so IIRC, there's a cam on the secondary side that activates the secondary metering system.
it's probably unrelated but i noticed that my stereo speakers sounded like they were shorting out at the same time the car was stumbling - i turned off the radio and turned it back on and they sounded normal again until the car cut out or bogged or whatever and then they sounded shorted out again - i unhooked all the stuff for the radio and it still has the hesitation -
that sounds like either a ground problem affecting the entire electrical system or interferience from the ignition system. check the ignition first. make sure the wires are fully connected and not melted by the headers or anything like that. also make sure that the coil has good solid power and ground. what are the spark plugs gapped at? i suggest pulling one out to double check the condition and color.
make sure you have a groung strap from the battery to the engine and body. and the engine to the body should be grounded too.
make sure you have a groung strap from the battery to the engine and body. and the engine to the body should be grounded too.
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